If you trust them, which it seems like you do, to not sell your information for advertising purposes then maybe thats true.
They're still sharing your personal information with others. Maybe you trust Google to not use the information stored in your drive for ads or to sell you shit but do you then also implicitly trust every corporation that that give that data to? To you then also trust those companies to always handle and treat your personal information with the respect it deserves for all time?
Hey! It's not that simple! There's feces too.